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Ag_Ag3PO4_g-C3N4复合光催化剂的合成与再生及其可见光下的光催化性能
[Article]物理化学学报(Wuli Huaxue Xuebao )Acta Phys.-Chim.Sin .2014,30(4),729-737April Received:December 9,2013;Revised:February 24,2014;Published on Web:February 24,2014.∗Corresponding author.Email:wyfwyf53540708@;Tel:+86-139********.The project was supported by the National Natural Science Foundation of China (21206105,21176168).国家自然科学基金(21206105,21176168)资助项目©Editorial office of Acta Physico -Chimica Sinicadoi:10.3866/PKU.WHXB 201402243Ag/Ag 3PO 4/g-C 3N 4复合光催化剂的合成与再生及其可见光下的光催化性能刘建新王韵芳*王雅文樊彩梅(太原理工大学洁净化工研究所,太原030024)摘要:研究了用离子交换沉淀法制备的Ag/Ag 3PO 4/g-C 3N 4的可见光光催化性能及再生方法.通过X 射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、紫外-可见(UV-Vis)吸收光谱及X 射线光电子能谱(XPS)对其进行了结构特性分析.XRD 结果显示再生后催化剂的结构未发生改变.FESEM 及UV-Vis 分析结果说明催化剂由Ag 3PO 4与g-C 3N 4复合而成.XPS 分析结果表明催化剂表面出现少量的银单质.利用可见光(λ>420nm)照射下的苯酚降解实验评价了样品的光催化活性,并通过活性物种及能带结构的分析对催化剂的光催化机理进行了推测.研究表明,Ag/Ag 3PO 4/g-C 3N 4的光催化活性明显高于纯Ag 3PO 4及纯g-C 3N 4,主要原因归结为单质银、Ag 3PO 4及g-C 3N 4的协同效应.经过氧化氢和磷酸氢铵钠(NaNH 4HPO 4)的再生可完全恢复催化剂的活性,这表明该绿色环保的再生方法可实现Ag/Ag 3PO 4/g-C 3N 4催化剂在环境中的实际应用.关键词:磷酸银;g-C 3N 4;金属银;催化剂再生;苯酚;光催化中图分类号:O644;O649Synthesis,Regeneration and Photocatalytic Activity under Visible-LightIrradiation of Ag/Ag 3PO 4/g-C 3N 4Hybrid PhotocatalystsLIU Jian-XinWANG Yun-Fang *WANG Ya-WenFAN Cai-Mei(Institute of Clean Technique for Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,P .R.China )Abstract:Ag/Ag 3PO 4/g-C 3N 4(g denotes graphitic)was synthesized via an anion-exchange precipitation method,and its photocatalytic activity under visible light and regeneration with H 2O 2and NaNH 4HPO 4were investigated.The structural characteristics were analyzed using X-ray diffraction (XRD),field-emission scanning electron microscopy (FESEM),ultraviolet-visible (UV-Vis)absorption spectroscopy,and X-ray photoelectron spectroscopy (XPS).The XRD results showed that the structure of the regenerated catalyst was unchanged.The FESEM and UV-Vis absorption spectroscopy results showed that the Ag/Ag 3PO 4/g-C 3N 4catalyst was composed of Ag 3PO 4and g-C 3N 4.XPS showed that a small amount of Ag particles were present on the catalyst surface.The photocatalytic activity was evaluated using phenol degradation under visible light (λ>420nm)and the photocatalytic mechanism was discussed based on the active species during the photocatalytic process and the band structure.Experimental studies showed that the photocatalytic activity of the as-prepared Ag/Ag 3PO 4/g-C 3N 4was higher than those of pure Ag 3PO 4and g-C 3N 4.The high photocatalytic performance of the Ag/Ag 3PO 4/g-C 3N 4composite can be attributed to the synergistic effect of Ag 3PO 4,g-C 3N 4,and a small amount of Ag 0.Regeneration using H 2O 2and NaNH 4HPO 4∙4H 2O fully restored the photoactivity of the catalyst,showing that this green regeneration method could make Ag/Ag 3PO 4/g-C 3N 4an environmentally friendly catalyst for practical applications.729Acta Phys.-Chim.Sin.2014V ol.301IntroductionThe quest for solar-energy utilization has led to the search for functional semiconductor photocatalysts that can directly split water and photodegrade organic pollutants.Accordingly, exploring novel functional materials,such as development of new monomer photocatalysts,graphene-based composite pho-tocatalysts,metal core/semiconductor shell nanocomposites, have become research focus.1-12Ye et al.13reported Ag3PO4as a new type of photocatalyst that exhibits extremely high photo-oxidative capabilities for O2evolution from water and for de-composing organic dyes under visible-light irradiation.The quantum efficiency of Ag3PO4is significantly higher than that of currently known visible light photocatalysts,such as g-C3N4, N-doped TiO2,and BiVO4.14-16Ag3PO4photocorrodes and decomposes to weakly active Ag during photocatalysis,and trace amount of silver as an electron scavenger can improve quantum efficiency and photocatalytic activity.Unfortunately,the photolysis of a large amount of Ag3PO4results in catalyst deactivation,and excess elemental silver affects catalyst contact with sunlight,thereby seriously hampering the practical application of Ag3PO4in photocataly-sis.To solve this problem,many composite photocatalysts, such as AgX(Br,I)/Ag3PO4,17,18TiO2/Ag3PO4,19Ag/Ag3PO4/g-C3N4,20and Ag3PO4/SnO2,21have been developed,and very good results have been achieved.Interestingly,Wang et al.22pro-posed a solution to the problem of recycling Ag from the photo-corrosion and decomposition of Ag3PO4using H2O2as a clean oxidant.However,their method cannot fully restore the catalyt-ic activity of Ag3PO4,and Ag3PO4is lost during the degradation process because Ag3PO4is slightly soluble in aqueous solution, which affects the utilization of the precious metal silver.This study aimed to completely restore activity of photocat-alysts and to avoid the loss of Ag3PO4during catalyst prepara-tion and regeneration.To this end,insoluble g-C3N4was used with Ag3PO4for the chemisorption between g-C3N4and Ag3PO4 to prevent the dissolution of silver phosphate.H2O2and alka-line NaNH4HPO4were used to regenerate the used Ag/Ag3PO4/ g-C3N4hybrid composite photocatalysts that were recycled af-ter the photocatalytic degradation reactions.2Materials and methods2.1Preparation of fresh pure Ag3PO4,pure g-C3N4,and Ag/Ag3PO4/g-C3N4All the reagents were purchased from Sinopharm and used without further purification.Pure Ag3PO4was prepared by the ion-exchange method.About0.39g of AgNO3was dispersed in distilled water(30mL),and an aqueous solution of NaNH4HPO4∙4H2O(15.6mL0.05mol∙L-1)was added.After vigorous stirring for1h,the yellow precipitate was collected by centrifugation,rinsed with distilled water three times,and dried at150°C for4h to obtain Ag3PO4.Pure g-C3N4was pre-pared by heating urea to400°C for0.5h to obtain melamine, and then heating was continued at575°C for2h.To prepare Ag/Ag3PO4/g-C3N4hybrid photocatalysts,the as-prepared g-C3N4power(0.1g)was dispersed in30mL of distilled water under ultrasonication for30min.About0.39g of AgNO3was added to ensure the molar ratio of Ag3PO4to g-C3N4is1:3, which is the optimum ratio,and the mixture was stirred at room temperature.NaNH4HPO4∙4H2O(15.6mL0.05mol∙L-1) was then added dropwise with continuous stirring for1h.The obtained solid product was centrifuged,washed,and dried at 150°C for4h.2.2Catalyst regenerationAfter phenol photodegradation in an aqueous solution under visible-light irradiation,the photocatalyst Ag/Ag3PO4/g-C3N4 was centrifuged,washed three times with distilled water,and dried at150°C for4h.In a typical regeneration reaction,the used photocatalyst was dispersed in NaNH4HPO4aqueous solu-tion(20mL)after each use.Then,H2O2(15%)was added drop-wise to the above suspension until the end of reaction(no bub-ble release).The products were subsequently collected by cen-trifugation,washed three times with distilled water,and dried at150°C for4h.2.3Characterisation of photocatalystsThe crystalline phases of the samples were examined by an X-ray diffraction(XRD)instrument(Rigaku,D/max-2500)us-ing Cu Kαradiation(λ=0.15406nm)within the2θrange from 10°to80°.The accelerating voltage and applied current were 40kV and30mA,respectively,and the scan rate was8(°)∙min-1.Morphological analysis and product compositions were investigated by field-emission scanning electron microscopy (FESEM,Japan JSM-7001F).The light absorption properties of the samples were recorded on an ultraviolet-visible(UV-Vis)spectrophotometer.Elemental compositions were detected by X-ray photoelectron spectroscopy(XPS,Thermo,ESCAL-AB250Xi).The shift in binding energy caused by relative sur-face charges was referenced to the C1s peak of the surface ad-ventitious carbon.2.4Photocatalytic activityThe photocatalytic activities of Ag/Ag3PO4/g-C3N4and re-Ag/Ag3PO4/g-C3N4(regenerated composite photocatalyst)were evaluated by the photocatalytic degradation of phenol in an aqueous solution under visible-light irradiation.For photocata-lytic phenol degradation,0.07g of the as-prepared photocata-lysts was mixed with100mL of15mg∙L-1phenol solution. During photocatalysis,the samples were periodically with-drawn(sampling time of30min),centrifuged to separate the photocatalyst powder from the solution,and subjected to absor-Key Words:Silver phosphate;g-C3N4;Metallic silver;Catalyst regeneration;Phenol;Photocatalysis730LIU Jian-Xin et al.:Synthesis,Regeneration and Photocatalytic Activity under Visible-Light of Ag/Ag3PO4/g-C3N4 No.4bance measurements.The photocatalytic activity of the com-posites was compared with those of the pure g-C3N4and pureAg3PO4powders under the same experimental conditions.Theregenerated photocatalysts were used to repeat the same degra-dation experiment for three cycles to determine their photosta-bility.3Results and discussion3.1Catalyst characterisationX-ray photoelectron spectroscopy was carried out to deter-mine the chemical composition of Ag3PO4,Ag/Ag3PO4/g-C3N4,and re-Ag/Ag3PO4/g-C3N4,as well as the valence states of vari-ous species present therein.The binding energies obtained inthe XPS analysis were corrected for specimen charging by ref-erencing C1s to284.60eV.Photoelectron peaks of Ag,O,P,N,and C were clearly observed in the Ag/Ag3PO4/g-C3N4andre-Ag/Ag3PO4/g-C3N4hybrids,as shown in Fig.1(A),whichconfirmed the presence of Ag,O,P,N,and C in the compos-ites.The comparison of O1s spectra in Fig.1(B)revealed thatthe O1s peak was fitted using XPS PEAK software to separatelattice oxygen and adsorbed oxygen located at530.62and532.80eV,respectively.The presence of adsorbed oxygen canimprove photocatalytic efficiency.25For Ag3PO4,the binding en-ergies of Ag3d5/2and Ag3d3/2peaks were located at367.7and373.7eV,respectively,consistent with the presence of Ag+onthe pared with Ag3PO4,the binding ener-gies of Ag3d5/2and Ag3d3/2in the other samples shifted to368.2and374.2eV,26,27respectively,as shown in Fig.1(C).Thisresult indicated that Ag0particles existed on the photocatalystsurface.Given the electron-rich structure of C3N4units,theycan transfer their electron density to Ag3PO4by overlappingwith the p z orbitals of heterocyclic nitrogens during the prepara-tion of the catalyst,which have the exact symmetry of the high-est unoccupied p-type orbital in the Huckel model.23,24Conse-quently,Ag0particles are generated in the preparation of Ag/Ag3PO4/g-C3N4hybrid photocatalyst.However,the content ofAg0particles is too low to be detected by XRD(Fig.2)in thebulk phase of Ag/Ag3PO4/g-C3N4hybrid photocatalyst becauseC3N4is merely excited during the reaction of AgNO3and NaNH4HPO4∙4H2O.The positions of binding energies of the Ag3d5/2and Ag3d3/2peaks of re-Ag/Ag3PO4/g-C3N4were the same as those of Ag/Ag3PO4/g-C3N4,and the XRD of re-Ag/ Ag3PO4/g-C3N4had no diffraction peaks of Ag0,indicating that the electron transfer process from g-C3N4to Ag3PO4occurred during catalyst regeneration,which was the same as the elec-tron transfer process that occurred during catalyst preparation. The intensity of Ag in the re-Ag/Ag3PO4/g-C3N4much lower than that in the original Ag/Ag3PO4/g-C3N4should attribute to the oxidation of hydrogen peroxide.During the catalyst regen-eration process,hydrogen peroxide as an oxidant to convert Ag0to Ag+.Therefore,the content of Ag0on the surface of the cata-lyst is decreased,and the intensity of Ag in the re-Ag/Ag3PO4/g-C3N4is much lower than that in the original Ag/Ag3PO4/g-C3N4.However,there are a small portion of the metallic silver which was wrapped by colloid group produced during catalyst regen-eration still on the surface of catalyst,avoiding the oxidation in-duced by hydrogen peroxide.After drying the catalyst,the met-al silver wrapped in the colloid group was exposed on the sur-face of the catalyst.As a result,a small amount of Ag0still ex-ists on the surface of the catalyst after regeneration.The XRD patterns of Ag/Ag3PO4/g-C3N4hybrid photocata-lysts exhibited coexistence of g-C3N4and Ag3PO4(JCPDS No. 02-0931)phases.27,28The diffraction peak at38.07°(JCPDS No. 04-0783)assigned to Ag0was found in the XRD patterns of the first used Ag/Ag3PO4/g-C3N4after one recycling run,29indicat-ing that severe photocorrosion of Ag3PO4occurred during pho-todegradation reaction.However the diffraction peaks of Ag disappeared in the XRD patterns of the re-Ag/Ag3PO4/g-C3N4, Fig.1XPS spectra of the photocatalysts(A)survey XPS spectra;(B)O1s spectra;(C)Ag3d spectra.(a)Ag3PO4;(b)Ag/Ag3PO4/g-C3N4;(c)re-Ag/Ag3PO4/g-C3N4731Acta Phys.-Chim.Sin .2014V ol.30and the diffraction peaks of re-Ag/Ag 3PO 4/g-C 3N 4had no signif-icant difference from that of the fresh one except that the main diffraction peaks of re-Ag/Ag 3PO 4/g-C 3N 4at 33.26°are little higher than peaks of Ag/Ag 3PO 4/g-C 3N 4,which means that the crystallization of composite photocatalyst has been improved after photocatalyst regeneration.Thus,Ag 0derived from light corrosion process transformed to Ag 3PO 4during photocatalyst regeneration.Therefore,the method of photocatalyst regenera-tion using NaNH 4HPO 4and H 2O 2(15%)effectively regenerated the composite photocatalyst.Fig.3shows the SEM images of Ag 3PO 4,re-Ag 3PO 4,Ag/Ag 3PO 4/g-C 3N 4,re-Ag/Ag 3PO 4/g-C 3N 4,and g-C 3N 4.Fig.3(A,B)reveals that both Ag 3PO 4and re-Ag 3PO 4particles had irregular spherical morphologies and non-uniform diameters.The mean size of Ag 3PO 4was estimated to be 100-500nm.However,the re-Ag 3PO 4particles obtained by photocatalyst regeneration were more regular in shape and homogeneous in distribution (Fig.3(B)).This finding was due to the rearrangement of Ag 3PO 4particles rebuilt from Ag during regeneration,with colloid coagulation and violent gas release.This variation in shape and distribution can be attributed to diffusion-limited aggregation and/or reaction-limited aggre-gation.30Fig.3(E)shows that g-C 3N 4had an irregular layered structure.The SEM images of Ag/Ag 3PO 4/g-C 3N 4and re-Ag/Ag 3PO 4/g-C 3N 4demonstrated a close connection between g-C 3N 4and Ag 3PO 4semiconductors (Fig.3(C,D)).No obvious sign of the presence of silver was observed because Ag was microscale.Importantly,all of them had the dimensionality,unique absorption edges,and morphologies of the original g-C 3N 4and Ag 3PO 4semiconductors.31Considering the different morphologies between Ag 3PO 4and re-Ag 3PO 4,the regeneration process markedly affected the morphology of re-Ag/Ag 3PO 4/g-C 3N pared with fresh Ag/Ag 3PO 4/g-C 3N 4,the layered structures of re-Ag/Ag 3PO 4/g-C 3N 4were more structured,and the distributions of Ag 3PO 4particles in the g-C 3N 4were more homogeneous.The UV-Vis diffuse reflectance measurements of pure g-C 3N 4,pure Ag 3PO 4,Ag/Ag 3PO 4/g-C 3N 4,and re-Ag/Ag 3PO 4/g-C 3N 4are shown in Fig.4(A).The absorption bands of Ag/Ag 3PO 4/g-C 3N 4and re-Ag/Ag 3PO 4/g-C 3N 4were almost identical in UV-Vis diffuse reflectance.This result further illustrated that this method of regenerating phosphorylation silver catalyst can restore the catalytic performance of the composite photocata-lyst.g-C 3N 4and Ag 3PO 4are direct-transition semiconductors.32,33Thus,the plot of (αh ν)1/2versus h νyielded the band gaps of pure g-C 3N 4,pure Ag 3PO 4,Ag/Ag 3PO 4/g-C 3N 4,and re-Ag/Ag 3PO 4/Fig.2XRD patterns of the photocatalysts(a)Ag/Ag 3PO 4/g-C 3N 4;(b)used-Ag/Ag 3PO 4/g-C 3N 4;(c)re-Ag/Ag 3PO 4/g-C 3N 4.A:Ag 3PO 4,C:g-C 3N4Fig.3SEM images of the photocatalysts(A)Ag 3PO 4;(B)re-Ag 3PO 4;(C)Ag/Ag 3PO 4/g-C 3N 4;(D)re-Ag/Ag 3PO 4/g-C 3N 4;(E)g-C 3N 4732LIU Jian-Xin et al .:Synthesis,Regeneration and Photocatalytic Activity under Visible-Light of Ag/Ag 3PO 4/g-C 3N 4No.4g-C 3N 4,as shown in Fig.4(B).Here,αand νare the adsorption coefficient and light frequency,respectively.The conduction band (CB)and valence band (VB)potentials of Ag 3PO 4and g-C 3N 4were determined to explain the mecha-nism of action of the synthesized photocatalysts.For a semi-conductor,CB and VB were calculated according to the follow-ing empirical equation:E CB =χ−E e −0.5E g E VB =E CB +E gwhere E CB and E VB are the CB and VB edge potentials,respec-tively;χis the electronegativity of the semiconductor,which is the geometric mean of the electronegativity of the constituent atoms;E e is the energy of free electrons on the hydrogen scale (about 4.5eV);and E g is the band-gap energy of the semicon-ductor.The calculated values of the CB and VB potentials of Ag 3PO 4and g-C 3N 4are listed in Table 1.3.2Photocatalytic performanceThe photocatalytic activities of as-prepared samples were evaluated by phenol degradation under visible light (>420nm).A phenol-photolysis test was also conducted for the same dura-tion under visible-light irradiation in the absence of catalyst.The blank test confirmed that phenol cannot be degraded with-in 120min under visible-light irradiation,indicating that phe-nol was a stable molecule and photolysis can be ignored.The photocatalytic efficiency of Ag/Ag 3PO 4/g-C 3N 4hybrid photocat-alysts was higher than those of pure g-C 3N 4and Ag 3PO 4as shown in Fig.5,which was calculated according to the absor-bance of solution at 270nm assigned to phenol.The cause of the photoactivity of Ag 3PO 4with 60min visible-light irradia-tion seemingly even better than that at 120min illumination is that some by-products had been generated during the photode-gration by pure Ag 3PO 4and the absorption of phenol at 270nm treated as the basis for calculating degradation rate is no longer applicable for system including a variety of materials.So,for the photodegration by pure Ag 3PO 4,the reduction of absorption of phenol at 270nm does not mean degradation of phenol.A more detailed demonstration was shown in Fig.6(A,B).During the photodegradation by pure Ag 3PO 4,the absorption peak at 244nm (the absorbance of 5mg of benzoquinone was deter-mined in all temporal absorption spectral patterns)that was rep-resentative of benzoquinone was observed in the absorption spectra.29And the irregular fluctuations of absorption of benzo-quinone and phenol during the whole photodegradation caused the absorption of phenol with 60min visible-light irradiation even lower than that at 120min illumination.Furthermore,the color of solution of phenol became pale yellow from colorless during the photodegration by pure Ag 3PO 4(the possible inter-mediates of degradation process of phenol are colorless except benzoquinone that is pale yellow solution),which is the further evidence of the existence of benzoquinone.Therefor phenol was not degraded and merely mutually transformed with benzo-quinone which was more toxic than phenol in aqueous solu-tion.However,during the same photodegradation of Ag/Ag 3PO 4/g-C 3N 4hybrid photocatalysts,the absorption peak of phenol was weakened,and no absorption peak of additional substances was observed in the absorption spectra of phenol.The same trend was found in the temporal absorption spectral patterns of phenol during photodegradation using re-Ag/Ag 3PO 4/g-C 3N 4and re-Ag 3PO 4,as shown in Fig.6(C,D),respec-Fig.4UV -Vis spectra and band gaps of as-synthesized samples(A)UV-Vis spectra;(B)band gaps.(a)Ag 3PO 4;(b)Ag/Ag 3PO 4/g-C 3N 4;(c)re-Ag/Ag 3PO 4/g-C 3N 4;(d)g-C 3N 4Table 1Calculation results of the CB and VB potentials ofAg 3PO 4and g-C 3N 4Ag 3PO 4g-C 3N 4χ5.964.55E g /eV 1.92.5E CB /eV 0.51-1.20E VB /eV 2.411.30Fig.5Photocatalytic degradation of phenol as a function of irradiation time under visible-light irradiation(a)phenol photolysis;(b)g-C 3N 4;(c)Ag 3PO 4;(d)Ag/Ag 3PO 4/g-C 3N 4733Acta Phys.-Chim.Sin.2014V ol.30tively.Conclusively,the Ag/Ag3PO4/g-C3N4hybrid photocatalysts effectively degraded phenol and possessed more excellent pho-tocatalytic properties than pure Ag3PO4and g-C3N4photocata-lysts.And the method of catalyst regeneration completely re-stored the activity of Ag/Ag3PO4/g-C3N4hybrid photocatalysts.3.3Recycling of Ag/Ag3PO4/g-C3N4and re-Ag/Ag3PO4/g-C3N4Fig.7shows cycling runs for the photocatalytic degradation of phenol in the presence of used Ag/Ag3PO4/g-C3N4without any regeneration process and re-Ag/Ag3PO4/g-C3N4regenerated after each photodegradation experiment in aqueous solution un-der visible-light irradiation.For Ag/Ag3PO4/g-C3N4hybrid pho-tocatalysts without regeneration,the rate of phenol degradation under visible-light irradiation significantly decreased in three successive experimental runs.However,under the same condi-tions,the ultimate degradation rate of phenol under visible-light irradiation for re-Ag/Ag3PO4/g-C3N4nearly had no difference from fresh Ag/Ag3PO4/g-C3N4hybrid photocatalysts.This re-sult indicated that the photocatalyst regeneration method using H2O2and NaNH4HPO4effectively restored photocatalytic activ-ity.More importantly,the method can be used continuously without restrictions.3.4Mechanism of Ag3PO4regeneration from AgAg3PO4is known to facilitate easy photolysis.When Ag3PO4 was used as a photocatalyst without a sacrificial reagent,13 Ag3PO4photocorroded and decomposed to weakly active Ag during photodegradation.A small amount of silver as an elec-tron-capture agent contributed to photocatalytic activity.35How-ever,as the reaction proceeded,the increase in silver content hindered contact between Ag3PO4and illumination.Conse-quently,photocatalytic activity gradually deteriorated,thereby limiting the practical application of Ag3PO4as a recyclable highly efficient photocatalyst.In the case of pure Ag3PO4and Ag/Ag3PO4/g-C3N4,the yellow catalysts were observed to dark-en when the photocatalytic reaction was completed.This phe-nomenon confirmed that Ag+in Ag/Ag3PO4/g-C3N4and Ag3PO4 decomposed to Ag0.The redox potential of the Ag+/Ag pair is0.80V,whereas in the presence of a mass of PO43-ions,the redox potential of Ag species markedly decreased to0.45V(Ag3PO4/Ag).36The H2O2/ OH-pair has a redox potential of0.867V in alkalinecondi-Fig.6Temporal absorption spectra of phenol dye during thephotodegradation process(A)Ag/Ag3PO4/g-C3N4;(B)Ag3PO4;(C)re-Ag/Ag3PO4/g-C3N4;(D)re-Ag3PO4Fig.7Cycling runs for the photocatalytic degradation of phenolunder visible-light irradiation(a)Ag/Ag3PO4/g-C3N4;(b)re-Ag/Ag3PO4/g-C3N4734LIU Jian-Xin et al .:Synthesis,Regeneration and Photocatalytic Activity under Visible-Light of Ag/Ag 3PO 4/g-C 3N 4No.4tions,which is higher than that of Ag 3PO 4/Ag.More important-ly,H 2O 2can oxidize Ag without contaminating the system with any impurity.17Thus,hydrogen peroxide as a clear oxidant can oxidized Ag 0to Ag +.The acid environment of their aqueous so-lution can dissolve Ag 3PO 4,and the decomposition rate of H 2O 2was fast.Thus,the weakly alkaline NaNH 4HPO 4was chosen asthe PO 43-source to prevent the loss of Ag 3PO 4.Once H 2O 2was added dropwise to the beaker with NaNH 4HPO 4aqueous solution and the precipitate of used pho-tocatalyst (used-Ag 3PO 4or used-Ag/Ag 3PO 4/g-C 3N 4)during re-generation,severe outgassing was observed and the boundaries between solution and precipitate disappeared.For Ag/Ag 3PO 4/g-C 3N 4,the used-Ag/Ag 3PO 4/g-C 3N 4transformed to g-C 3N 4/Ag 3PO 4/Ag 2O (colloid),and colloid coagulation occurred with g-C 3N 4/Ag 3PO 4/Ag 2O (colloid)and NaNH 4HPO 4.At the same time,electrons of g-C 3N 4transferred to Ag 3PO 4similar to the transfer that occurred during preparation,and the final product Ag/Ag 3PO 4/g-C 3N 4containing only a minimal content of silver was obtained.The reaction process of Ag 3PO 4also applied to pure Ag 3PO 4,which followed the reaction below:4Ag+4H 2O 2=2Ag 2O (colloid)+4H 2O+O 2(1)3Ag 2O+2PO 43-+6H +=2Ag 3PO 4+3H 2O (2)After the easy regeneration reaction using H 2O 2with NaNH 4HPO 4,the color of Ag/Ag 3PO 4/g-C 3N 4returned from black to pale yellow,the majority of Ag 0disappeared and be-came Ag 3PO 4,and the activity of the composite photocatalyst was restored.Although there is the appearance of chromatic ab-erration between Ag/Ag 3PO 4/g-C 3N 4and re-Ag/Ag 3PO 4/g-C 3N 4as shown in Fig.8for the changes of crystal form and morphol-ogy of the photocatalyst during the colloid coagulation,no ob-vious change was observed in photocatalytic activity.It can be concluded that the catalyst regeneration method used using H 2O 2and NaNH 4HPO 4is effective.3.5Detection of reactive oxygen speciesDuring photocatalytic oxidation,a series of reactive oxygen species,such as h +,∙OH,or O 2-●,are supposed to be involved.To examine the role of these reactive species,the effects ofsome radical scavengers and N 2purging on phenol photodegra-dation were investigated to propose a reaction pathway.The ex-periment on identifying reactive oxygen species was similar to the photodegradation experiment.Different quantities of scav-engers were introduced into the phenol solution prior to cata-lyst addition.In this study,tert-butanol (TB)was added to the reaction system as an ∙OH scavenger,and ammonium oxalate (AO)was introduced as a scavenger of h +.N 2purging was thenadopted to quench O 2-●.37-39Fig.9shows that in the presence of scavengers or when N 2purging was conducted,phenol photodegradation was inhibited in varying degrees compared with no scavenger under the same conditions,indicating that all reactive oxygen species act-ed together for phenol degradation.This finding suggested that phenol photodegradation by Ag/Ag 3PO 4/g-C 3N 4hybrid photo-catalysts was a collaborative process of all reactive oxygen spe-cies.This process differed from methyl orange (MO)photodeg-radation under the same conditions,wherein dissolved O 2had no effect on photodegradation under visible-light irradiation.35This experimental result proved that Ag/Ag 3PO 4/g-C 3N 4hy-brid photocatalysts produced a variety of active substancesthatFig.8Schematic diagram for the processes of the photodegradation,regeneration,and recycling of Ag/Ag 3PO 4/g-C 3N4Fig.9Effects of different scavengers on the degradation of phenol in the presence of Ag/Ag 3PO 4/g-C 3N 4photocatalystsunder visible-light irradiation(a)ammonium oxalate;(b)tert -butanol;(c)N 2purging;(d)no scavenger735Acta Phys.-Chim.Sin.2014V ol.30jointly played an important role in phenol photodegradation un-der visible-light irradiation.3.6Mechanism of improved photocatalysisThe photocatalytic activity of catalysts depends on many fac-tors affecting photocatalysts,such as efficient charge separa-tion,surface property,morphology,optical property,and size.Meanwhile,the properties and characteristics of target organicpollutants affect photodegradation efficiency.41-46In our case,the photodegradation capability of both pure Ag3PO4and pureg-C3N4was insufficient for complete phenol degradation,be-cause this process generated other byproducts or had very lowdegradation efficiency.However,the photocatalysis resultsshowed the excellent photoactivity of the Ag/Ag3PO4/g-C3N4composite samples on phenol degradation,indicating that thecombination of g-C3N4and Ag3PO4was feasible and practical.Based on the above results and current literature,20,22,31,35a mechanism was proposed to explain the enhanced photocatalyt-ic activity of Ag/Ag3PO4/g-C3N4photocatalysts for phenol un-der visible-light irradiation.The energy band edge position be-tween g-C3N4and Ag3PO4and the corresponding enhancement of redox ability were found to improve the photocatalytic abili-ty of Ag/Ag3PO4/g-C3N4photocatalysts for phenol.In general,a more positive VB top corresponded to stronger oxidation abili-ty,and a more negative CB bottom corresponded to stronger re-duction ability.17In the process of photocatalytic reaction by Ag/Ag3PO4/g-C3N4photocatalysts under visible-light irradiation, both Ag3PO4and g-C3N4were excited,and the photogenerated electrons and holes were in their CB and VB,respectively.The electrons in the CB of g-C3N4with a more negative potential displayed strong reduction power,whereas holes in the VB of Ag3PO4showed strong oxidation ability.In more detail,the CB edge potential of g-C3N4(E CB=-1.2eV vs NHE(normal hydro-gen electrode))was more negative than E0(O2/O2-●)(-0.286eV vs NHE)and E0(O2/H2O2)(+0.286eV vs NHE).This finding in-dicated that e-can directly reduce the adsorbed O2molecules into O2-●radicals and H2O2.Moreover,the VB edge potentials of Ag3PO4(E VB=+2.51eV vs NHE)were more positive than E0 (∙OH/H2O)(+2.27eV vs NHE),which demonstrated that the h+of Ag3PO4can provide sufficient potential to oxidise H2O to∙OH.The Ag/Ag3PO4/g-C3N4photocatalysts can simultaneous-ly produce a variety of active substances that cooperatively act on the organic substance,consistent with the finding of the ex-perimental detection of reactive species.Then,all active sub-stances simultaneously reacted with phenol,which differed from the interpretation of some previous studies that organic pollutants react with only one active substance at the same time.40The exclusive use of pure Ag3PO4or pure g-C3N4was unable to generate sufficient active substance because of the lack of redox ability.Additional,according to the Z-scheme principle,the photogenerated electrons moved from the CB bot-tom of Ag3PO4(0.51eV)to Ag0and then continued to shift to the VB top of g-C3N4(1.5eV),recombing with the holes there as shown in Fig.10.47Conclusively,the photocatalytic ability of Ag/Ag3PO4/g-C3N4that can complete phenol degradation was due to the synergistic effects among Ag3PO4nanoparticles and the g-C3N4sheet.Some special properties of g-C3N4and Ag3PO4also affected the activity of the composite photocatalyst.The electronic con-ductivity of g-C3N4with a graphite-like structure accelerated the combination of e-and oxygen,reduced the recombination of electrons and holes,and enhanced the quantum efficiency of Ag/Ag3PO4/g-C3N4photocatalysts.For pure Ag3PO4,the ability to dissolve in water led to loss of photocatalytic performance. Given the chemical adsorption between g-C3N4and Ag3PO4, the insoluble g-C3N4sheet can protect Ag3PO4from dissolution in aqueous solution.4ConclusionsFor application of semiconductor in the field of photocataly-sis,photocatalytic activity and recyclable use of photocatalyst were the most critical factors.In this paper,Ag/Ag3PO4/g-C3N4 hybrid photocatalysts containing traces of silver were easily synthesized,which exhibited great higher photocatalytic activi-ty than pure Ag3PO4or pure g-C3N4for phenol photodegrada-tion under visible-light irradiation(>420nm).And H2O2and NaNH4HPO4were adopted to regenerate Ag3PO4from weak photocatalytically active Ag as a recyclable highly efficient photocatalyst,which almost completely restored the catalytic activity.More importantly,the method of synthesis and regen-eration of Ag/Ag3PO4/g-C3N4hybrid photocatalysts was green, simple,and repeatable.References(1)Fujishima,A.;Honda,K.Nature1972,238(5358),37.doi:10.1038/238037a0(2)Hagfeldt,A.;Grätzel,M.Chem.Rev.1995,95(1),49.doi:10.1021/cr00033a003(3)Chen,W.;Dong,X.F.;Chen,Z.S.;Chen,S.Z.;Lin,W.M.Acta Phys.-Chim.Sin.2009,25(6),1107.[陈威,董新法,陈之善,陈胜洲,林维明.物理化学学报,2009,25(6),1107.] Fig.10Schematic diagram of possible reaction mechanism over Ag/Ag3PO4/g-C3N4hybrid photocatalyst undervisible-light irradiation736。
智慧教学创新研究的探索与实践
Science and Technology &Innovation ┃科技与创新2021年第01期·137·文章编号:2095-6835(2021)01-0137-02智慧教学创新研究的探索与实践*汪芳(武汉华夏理工学院智能制造学院,湖北武汉430223)摘要:智慧教学的发展,带来了教与学的重大变革。
武汉华夏理工学院推广新型教学理念,促进信息化技术在教学过程中的深度应用,积极探索基于新技术的教育教学模式改革,在智慧教学方面做了大量工作,并取得了一定的成果。
关键词:智慧教学;在线课程;直播授课;“互联网+”课堂教学模式中图分类号:G434文献标志码:ADOI :10.15913/ki.kjycx.2021.01.053智慧教学即教学信息化,指在教学过程中深入运用现代信息技术。
目前,传统教与学的方式已经不能满足学生移动学习、智慧学习的需求,在这种背景下,各高校抓住新的发展机遇,将信息技术与教育教学深度融合,加快在线开放课程建设和混合式教学改革进程。
武汉华夏理工学院在智慧教学方面也做了大量探索与实践,有计划地引进智慧教学工具,加强教师智慧教学能力培训,积极组织开展智慧教学模式的创新实践,不断探索和推进基于新技术的教育教学模式改革。
1大力推广新型教学理念和运用智慧教学工具1.1转变教师的教学观念和教学方法为增加教师对智慧教学的了解,推进智慧教学工具的使用,武汉华夏理工学院教师发展中心组织一批勇于教学实践、勤于教学创新、善于研究分享的教育教学实践先行者,成立智慧教学推广团队。
作为学校首批“智慧教学探索者”,面向全校教师开设了智慧教学工作坊,积极推广智慧教学改革理念,并创造性地运用“雨课堂”“学习通”“微助教”多种智慧教学工具开展各种教学工作,引导教师进行改革实践,帮助教师使用智慧教学工具进行课堂实践,解决教学中出现的问题,对推广智慧教学的新模式起到了带头示范作用,使课堂活跃起来、知识鲜活起来、学生专注起来;团队在全校范围内向各二级学院、各学科专业课程推广应用信息化教学工具,开展全校性的应用培训工作,搭建智慧教学技术支持平台,并率先在通识课、专业课、实践环节中应用“雨课堂”等多种智慧教学工具,进行“翻转课堂”教学改革探索,效果良好。
湖南省第三届徐特立研究论文评奖及学会2009年度立项课题评审结果
徐特立的民主办学思想与实践探析
论徐特 立的“ 群众本位” 教育观及其 当代价值
赵士启
吴振 尘 三等奖( 0 ) 1名 :
周树 森
Hale Waihona Puke 教 师应具有“ 先进分子” 的优 良素质
论徐特 立儿童去惩罚教 育观
徐 特 立— — 杰 出的无 产 阶级 教 育 家
江来登 孙光贵
徐特立政 治、 育思想发展 的转折 点— — 宁乡速成师范 教 徐特立 : 己欲立而立人 , 欲 达而达人 ” “ 己
委 托 课题 ( 项 ) 1 : 长沙师范学校思想政治理论课 部 徐特立思想言行与提 高思想政治理论课 实效性 的整合研 究 湖 南省 徐特 立 教 育思 想研 究 会
21 0 0年 1月 2 O日
来 稿 须 知
为 了推动我 国学术交流的繁荣与发展 , 有利于期刊事业的现代化 、 标准化、 规范化 , 本刊严格执 行《 中国学术期刊( 光盘版 ) 索与评价数据规范》c lC 检 ( A- D规范) 。所有来稿请参照该规 范 20 年 06 修 订 本进 行 必要 的修 改补 充 , 以利 于顺利发表 。 1来稿请通 过 电子邮件直接投稿 。 . 本刊 E—ma:s @cia u 1e. icz hnj mantn或 c fb 6 . ro l s o . c sx @13cn 请在 s o 主题栏 注明作 者及 文章 标题 。 2请 附作者详细资料 , . 包括 : 姓名、 出生年、 性别、 民族 、 籍贯、 职称、 学位 、 主要研究方向、 工作单
谷安仕 廖 义军 吴名 蒙
吴振 尘 彭红 霞 马 伶
“ 八办” 期间徐特立的青年工作 徐特 立与湖南农民运动 徐特立 苏区青年工作研 究
《基于标准样品的线性校准》国家标准通过审定
《基于标准样品的线性校准》国家标准通过审定
佚名
【期刊名称】《《中国标准导报》》
【年(卷),期】2010(000)003
【摘要】近日,全国统计方法应用标准化技术委员会在京召开了《基于标准样品的线性校准》国家标准审查会。
该标准是国家标准化管理委员会“2007年国家标准制修订项目计划”,由全国统计方法应用标准化技术委员会提出并归口,由辽宁出入境检验检疫局与我院等多家单位起草。
【总页数】1页(P44)
【正文语种】中文
【中图分类】F740.43
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湖北省2010年优秀学士学位论文获奖名单
导航卫星自主定轨时卫星机动问题的处理方法 内部控制信息披露研究 对现实基本公共卫生服务均等化的思考 马歇尔-勒纳条件在中国的实证分析 浅析美剧字幕组——互联网中“草根”翻译的崛起与狂欢 紧黎曼面间的调和映照 圆对称高斯分布声源声场分布的研究 基于GDF4.0的导航空间数据库建库研究 皮兰德娄《六个寻找剧作家的剧中人》研究 粘土电渗排水固结影响因素的试验研究 基于Lamb波及TR方法的加筋结构健康监测 水电站钢岔管辅助设计系统开发与应用 GLONASS导航卫星系统及GPS/GLONASS组合定位若干问题研究 数控切割机切割炬姿态角控制机构设计———扇形齿轮式结构的设 计 基于MgZnO的紫外发光二极管的制备及其电致发光性能的研 基于内容挖掘的智能化政务网站评价体系 关于中国外汇储备适度规模的实证研究——基于修正后缓冲存货模 型的分析 共青团组织的思想政治教育职能研究 基于SharpMap和GDAL/OGR的流域突发性环境风险预测系统的研究与 实现 基于MatLab的地图投影设计 基于无标度特性的对等网络高效资源搜索方法研究 PSInSAR技术监测地壳形变的个别问题研究---- PS点探测及阈值确 定 气候变化与低碳经济条件下的中美能源博弈 民国初年宪政建设的得失讨论——以宪政危机为出发点的观察 碱性SPE水电解电极扩散层与阳极催化剂研究
武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学 武汉大学
101 基于地理信息系统平台的武汉道路交通事故分析研究 102 地理案例推理在地理时空过程中的应用研究 103 基于单片FPGA的高速高分辨率的JPEG图像压缩编码器的设计与实现 104 内蒙古河套灌区节水改造与续建配套规划 105 对流层投影函数对PPP定位结果的影响研究 106 论钢琴演奏者心理活动对钢琴学习和演奏的影响 107 境外企业境内上市与境内股东权的保护 108 从四篇政治论文看梭罗的多重自我 109 双语跨语言的句法长时启动效应研究 110 砚瓦石水库大坝及溢洪道除险加固设计 111 湖北省洪湖隔堤北灌区续建改造规划设计——集中建泵方案 112 饮酒后致不能安全驾驶入刑研究 113 爱伦坡短篇小说功能文体学分析 A Functional Stylistics Approach to Edgar Allan Poe’s Short Stories
文献信息检索课教学改革探讨与实践——以中南大学湘雅医学院医药信息系为例
讲义 的重 复再 现 , 这些 问题 的普遍 存在 , 使学 生失 去 了学 习 的兴趣 , 不到 应有 的教学 效果 。 响 了学 生 达 影 对信 息检 索知识 的获取 和检 索能 力的提 高 。 1 教 学方 法不适 应 学生 的发展 需求 . 4 现行 的文 献信 息检 索课程 的教 学 大都还 是 以教 师的讲授为主 ,教师习惯于把现成的知识输入学生 的头 脑 , 调 的是知识 的传 递 , 这 种 以教 师 、 堂 强 在 课 和书 本 为 中心 的教 学模 式 中 。学 生总 是在 被动地 接 受知 识 和信 息 。虽 然有 的教 师也 尝试 着使 用启 发式 教学方 法 、 案例 式教 学方 法 , 由于对教 学方 法 的研 但 究不 透彻 。 或是 由于种种 原 因实践 不到 位 , 检课 的 文 教学 方法 还是 不适 应学 生 的发展需 求 .教学 质量 有 待提 高 。 而且 很 多不 同学科 和专业 的学生一 起上课 , 这样 学生 多 、 科 杂等 多种原 因 , 大 了文检 课 的教 学 加 学组织难 度 。
随 着 网络 时代 的发 展 以 及 学 生 规 模 的 不 断 扩 大 , 献信 息检 索课 ( 称 “ 文 简 文检 课 ” 的教学 内容 、 ) 教 学 方法 、教学 手段 、教学 模式 等存 在一 些与 学生 需 求 、 生 成 长 不相 适 应 的地 方 , 学 亟待 进 行改 革探 索 。 研 究和 探 索适 合 网络 时代 条件 下 的文检课 教 学模 式 是 一项 重要 和 紧迫 的任务 。 1 文 献信 息检 索课教 学存 在 的问题
2009年科技论文评选结果
缩 短 主机组 装周期 5 0 WT 区加强 型成 品油船 自 1 0D 冰 8 动舵 系统调 试
庄永校
彭贵兵 李 木荣
H R 2 不锈 管的 内场制作 D g相
周 惠芳
生产 设计 如何提 高钢材利 用率
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关于中国传统色彩在现代视觉传达设计中的应用研究
关于中国传统色彩在现代视觉传达设计中的应用研究Research on the application of traditional Chinese colors in modern visual communication design刘冰雪/海南大学国际传播与艺术学院刘思雨/北京化工大学朱慧芳 杨洁/ 海南大学国际传播与艺术学院Liu Bingxue/School of International Communication and Art,Hainan UniversityLiu Siyu/ Beijing University of Chemical TechnologyZhu Huifang,Yang Jie/School of International Communication and Art, Hainan University摘 要:中国传统颜色在传统文化中具有特殊含义和象征,将现代视觉传达设计与中国传统色彩进行有机融合,可以提升设计作品的艺术气息和文化内涵。
因此,设计人员在视觉传达设计过程中,要根据设计作品的需求和特征适当地选择中国传统色彩,使设计作品色彩搭配更加分明、科学、合理,推动中国传统色彩在现代视觉传达设计中的应用,以提升视觉传达设计整体效果。
关键词:中国传统色彩;视觉传达设计;现代设计Abstract: Traditional Chinese colors have special meanings and symbols in traditional culture. The organic integration of modern visual communication design and traditional Chinese colors can enhance the artistic atmosphere and cultural connotation of design works. Therefore, in the process of visual communication design, designers should appropriately select traditional Chinese colors according to the needs and characteristics of design works, so as to make the color collocation of design works more clear, scientific and reasonable, and promote the application of traditional Chinese colors in modern visual communication design to improve the overall effect of visual communication design.Keywords: Chinese traditional color; Visual communication design; Modern design0 引言从中国传统绘画发展到现代视觉传达设计,都极为重视对色彩的搭配和使用,以提升设计作品的内涵、效果、艺术气息、情感传达。
浅谈标准文献分类的现状及改革设想
浅谈标准文献分类的现状及改革设想
邵卫东
【期刊名称】《大学图书情报学刊》
【年(卷),期】1994(000)004
【摘要】标准文献是一种特殊类型的文献,它的数量较多,涉及学科门类广泛,更新替换频繁,如何对其妥善地管理,令许多图书情报部门都颇感棘手。
而另一方面,标准文献又是一种法规性文献,它对于推动科技进步、促进社会发展及在社会生活的许多方面有着很强的规范和指导作用,其使用率相当
【总页数】4页(P4-7)
【作者】邵卫东
【作者单位】淮南矿业学院
【正文语种】中文
【中图分类】G255.54
【相关文献】
1.《中国标准文献分类法》与《国际标准分类法》在我国标准文献中的应用 [J], 程军毅
2.浅谈职业院校计算机专业教学现状及改革设想 [J], 王倩
3.浅谈财经证劵类电视节目现状及改革设想 [J], 刘丽彬;
4.专科学校人体解剖学教学的现状及改革设想浅谈 [J], 肖楚丽
5.浅谈商品差价的现状及改革设想 [J], 戴中久
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论中国古代中医学与法医学之隔阂与关联
论中国古代中医学与法医学之隔阂与关联刘雅芳,程伟(黑龙江中医药大学,黑龙江 哈尔滨 150040)摘 要:在中国古代,中医学之于法医学并没有发挥像今天现代医学指导司法检验这样的作用。
中医学与法医学在理论上存在着隔阂,但二者又藕断丝连的关联着。
尽管中国古代法医检验技术比较粗糙和原始,但它的实证观察精神是与现代法医学和现代医学相一致的,而这一点并没有被中医学所借鉴。
法医学没有促进中医学的发展,而中医学也不能解决法医学中的实际问题。
关键词:中医学;法医学;解剖中图分类号:R -05 文献标识码:A 文章编号:1002-2406(2008)05-0003-02作者简介:刘雅芳(1979-),女,现为黑龙江中医药大学2006级中医医史文献专业博士研究生。
研究方向:中国古代医学史。
收稿日期:2008-05-21修回日期:2008-07-101 中国古代的法医学中国古代法医学发源于战国时代,历史上相继出现了5疑狱集6、5内恕录6、5折狱龟鉴6、5棠阴比事6、5洗冤集录6、5无冤录6等法医著作。
唐、宋时期中国的法医学已成体系,元、明、清几代的检验制度基本上都是沿袭唐、宋的规定。
但在宋慈以后至清朝末年的600多年中,法医检验工作一直以5洗冤集录6为主要依据,停留在尸表检验上,未发生根本改变[1]。
到了19世纪,随着显微镜的出现和化学分析方法的应用,现代法医学逐渐发展起来。
专业的法医学人员要求掌握尸体解剖、损伤检查等基本方法与原理,掌握基础医学与临床医学的基本理论与操作技能等等。
相比较而言,古代的法医学是简陋的、经验性的和实用性的。
包括5洗冤集录6在内的所有法医著作的成就都是在外表检验中取得的。
造成这种情况的原因是负责验伤、验尸的官员和仵作不是由医生充当,操作者多是目不识丁的役人,主管人员多是科举出身的官员,医生的参与在法医检验中并不占据主导地位,中医理论也不能为法医验伤验尸提供可供参照的知识体系。
同时,中国古代法医著作中很多可贵的经验知识也没能为中医理论体系所采纳,没有对古代医学发展起到推动作用,对尸体解剖的禁止也限制了对人体的深入探究。
经典研读:开启个体成人的民族范型
经典研读:开启个体成人的民族范型
刘铁芳
【期刊名称】《湖南师范大学教育科学学报》
【年(卷),期】2022(21)6
【摘要】为什么我的眼里常含泪水?因为我对这土地爱得深沉……——艾青:《我爱这土地》生活在21世纪的今天,我们身处现代化的种种便利之中,为什么还需要不断地回到古典、回归经典?这本身就是一个问题。
借用艾青的说法,为什么我会如此眷顾古典教育研究,因为我对这片土地爱得深沉。
雅斯贝尔斯提出“轴心时代”的概念。
“这一世界史的轴心似乎是在公元前500年左右,是在公元前800年到公元前200年产生的精神过程。
【总页数】3页(P5-7)
【作者】刘铁芳
【作者单位】湖南师范大学教育科学学院
【正文语种】中文
【中图分类】I20
【相关文献】
1.研读教育经典提高教学水平——研读《给教师的建议》的收获与体会
2.研读教育经典提高教学水平——研读《给教师的建议》的收获与体会
3.多视角研读中国文化经典——以人教版《中国文化经典研读》为例
4.当代大学中国经典教育的初步探索——基于北京航空航天大学"中国经典研读"课程的思考
5.多视角研读中国文化经典——以人教版《中国文化经典研读》为例
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从中国传统文化的价值内涵看和谐社会
从中国传统文化的价值内涵看和谐社会
熊然
【期刊名称】《漯河职业技术学院学报》
【年(卷),期】2008(007)003
【摘要】中国传统文化的价值体系中已包含了和谐社会理念中一些基本内容.发扬中国传统文化对当前社会的精神文明建设具有积极的借鉴意义.中国传统文化深厚的价值内涵可以为构建和谐社会提供坚实的精神支柱.
【总页数】2页(P36-37)
【作者】熊然
【作者单位】湖北省社会科学研究所,湖北,武昌430077
【正文语种】中文
【中图分类】D334
【相关文献】
1.从法治的价值内涵看政府推进型法治之路 [J], 张楠
2.社会主义和谐社会的价值内涵及其运行规范 [J], 李希文
3.从世界遗产视角看北方民族传统文化价值内涵 [J], 李华明
4.复杂性科学视域下看“中国梦”的价值内涵 [J], 张毓芳妃
5.中国传统文化视域下和谐社会的构建\r——品读《诗经》中的\"和\"文化 [J], 刘晖;谢卫平
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中国人民大学出版社:学术沃土 思想摇篮
中国人民大学出版社:学术沃土思想摇篮
佚名
【期刊名称】《出版发行研究》
【年(卷),期】2008()3
【总页数】1页(PF0004-F0004)
【正文语种】中文
【中图分类】G
【相关文献】
1.把更多中国学术佳作推介给“一带一路”沿线国家——专访中国人民大学出版社国际出版中心主任刘叶华 [J], 徐来;
2.学术沃土思想摇篮--中国人民大学出版社成立五十周年 [J], 钟楚
3.以“规范”为准绳提高译稿质量——中国人民大学出版社学术类译著编辑规范介绍 [J], 杨宗元
4.学术沃土思想摇篮--在中国人民大学出版社成立50周年庆祝大会上的讲话 [J], 纪宝成
5.出教材学术精品,育人文社科英才中国人民大学出版社50年成就辉煌 [J], 方菊因版权原因,仅展示原文概要,查看原文内容请购买。
空间生产理论视角下的体育馆平急转换设计分析
空间生产理论视角下的体育馆平急转换设计分析
刘雅格
【期刊名称】《建设科技》
【年(卷),期】2024()9
【摘要】本文以列斐伏尔空间生产三元辩证理论视角为切入点,探寻大型灾难面前将体育馆改装为临时避难和收容场所使用时的设计策略和方法。
在感知空间的层面,设计者应充分考虑被收容者精神层次的安抚需求,以人文关怀为指导,将体育馆的空间职能从体育赛事柔和过渡到防灾避难收留;在认知空间的层面,设计者应合理高效的认识体育馆整体空间,通过立体多维的室内空间改造,在灾害时期向被收容者传达积极的精神指引;在体验空间的层面,设计者应既最大效率利用体育馆空间的同时,也要合理保障每个被收容者的隐私需求,尊重个体的生活节奏独立性。
【总页数】5页(P83-87)
【作者】刘雅格
【作者单位】香港城市大学工学院
【正文语种】中文
【中图分类】G63
【相关文献】
1.基于心理空间理论下的语篇视角转换
2.空间生产理论视野下大学图书馆空间研究范式的转换
3.城中村是城市未来的种子——列斐伏尔空间生产理论视角下的城市
空间研究4.空间生产视角下旧城非正规性街道空间研究——以厦门营平片区开元路为例5.历史古镇主体转换视角下的特色小镇空间生产
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从资源整合角度看继续教育的发展
从资源整合角度看继续教育的发展
刘雅丽
【期刊名称】《成人教育》
【年(卷),期】2008(000)009
【摘要】继续教育是实践终身教育思想的理想选择,继续教育资源是保障继续教育良性运转不可或缺的条件.继续教育资源的多寡、利用率以及整合优化状况决定继续教育办学的规模、办学的社会效益和继续教育事业的发展水平.
【总页数】2页(P44-45)
【作者】刘雅丽
【作者单位】衡阳师范学院,继续教育学院,湖南,衡阳,421008
【正文语种】中文
【中图分类】G72
【相关文献】
1.从北京大学继续教育的发展看改革开放对社会科学继续教育的推动
2.从企业兼并重组角度看山西煤炭资源整合——以山西煤炭进出口集团公司为例
3.从资源整合角度看企业并购的实施
4.从支点建设角度看鄂西圈特色资源整合开发——以大洪山、清江画廊为例
5.从中国科协的继续教育活动看科技团体在继续教育事业发展中的作用
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在医专的基础免疫学教学中系统讲授MHS的体会
在医专的基础免疫学教学中系统讲授MHS的体会
何海根
【期刊名称】《健康研究》
【年(卷),期】1994(000)004
【总页数】2页(P47-48)
【作者】何海根
【作者单位】
【正文语种】中文
【中图分类】R-4
【相关文献】
1.以工匠精神讲授医专计算机应用基础课程 [J], 李绪陵
2.在免疫学实验教学中以提出问题为基础的学习方式教学的几点体会 [J], 王立顺;常雅萍;李一
3.PBL结合数码互动系统在医专病理学实验教学中的应用研究 [J], 侯菊花;刘圆月;谢川;张文将
4.演示实验在单元电路教学中的作用——讲授电子技术基础课的几点体会 [J], 王纯
5.QQ群网络平台在基础免疫学教学中的应用建设成效与体会 [J], 石峰;李刚;李桂芳;张婷婷
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从无效程序看外观申请质量的提高
从无效程序看外观申请质量的提高
刘萌;杨凤云
【期刊名称】《中国发明与专利》
【年(卷),期】2015(000)007
【摘要】尽管以非三性条款被无效的案件数量比例不高,但其中反映的问题值得借鉴.如果当事人或者代理人在外观申请过程中更加熟悉相关规定,提高责任意识,或者选择更好的申请策略,则可避免事后被无效的境遇.
【总页数】5页(P84-88)
【作者】刘萌;杨凤云
【作者单位】国家知识产权局专利复审委员会;国家知识产权局专利复审委员会【正文语种】中文
【相关文献】
1.从“电风扇”无效案看外观设计新颖性的变化 [J], 李秀娟
2.巧用程序处理提高零件螺纹外观质量 [J], 王奇;沙磊
3.无效宣告程序中外观设计专利与在先商标权相冲突的判断 [J], 高桂莲
4.从日本关联外观设计制度的角度看日本外观申请策略 [J], 谢敏楠;松井宏记
5.从日本关联外观设计制度的角度看日本外观申请策略 [J], 谢敏楠;松井宏记因版权原因,仅展示原文概要,查看原文内容请购买。
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Multi-meaning of the Word “cover” and its E-C Translationin Business EnglishAbstract:With the economic globalization and frequent business activities, the importance of business English is becoming more and more outstanding. So the modern business English translation plays an ever-increasing role in international trade. Most of business English vocabularies are basic vocabularies, except some professional terms. When these basic vocabularies are applied to the business fields, most of them have special meanings, and this kind of situation also increases the difficulty for understanding and translation. In this thesis, the writer is going to introduce the multi-meaning of the word “cover”and its E-C translation in business English. With view to solving the translation problems of the word “cover” in business English, this paper points out that translators engaged in foreign business should pay extra attention to learning professional knowledge in business English, and understanding commercial language features, and studying translation skills set in the principle of correctness, rigorousness, and standardized consistency. This paper is to detail not only the meanings and usage s of “cover” functioning as noun and verb with rich examples but also the expres sions concerned. The word “cover” and its derivatives are illustrated in this paper for the purpose of further understanding and appropriate usage to the readers.Key words:business English; cover; derivatives; translation1 IntroductionSpelling of the word “cover” is simple, but this word is frequently used in many aspects. People naturally think of the equivalent Chinese language as long as they see it, such as “a thing that is put over or on another thing”, “to lie or spread over the surface of somet hing” and so on. But the interpretation of this word is far more than that, especially in business English. It has many different meanings in various documents (invoices and letters of credit) and different contract terms. We should translate itaccording to the specific occasions, sentence structures, word matches, understand the specific meanings, combine with the knowledge of foreign trade and use of translation skills flexibly. So sometimes it is difficult to understand. Translator should be careful to choose appropriate Chinese words to translate “cover” based on the concrete situational and linguistic contexts. The aspects of the text, from information to purpose of the text, force us to adapt relatively flexible methods in our translation practice. Therefore, the meanings and the Chinese equivalents of the word “cover” in different situation and linguistic contexts and clauses were studied. This paper discusses the multi-meaning and the E-C translation skills of the word “cover” and its derivatives in business English.In modern time the most influential norms were Yan Fu’s “faithfulness, expressiveness and elegance”on the one hand and Lu Xun’s principle “rather to be faithful in thought than smooth in the language” on the other. Both Yan Fu and Lu Xun laid much stress on the principles of being faithful. This principle is also the most important point in business translation.2 Meanings and Usages as a NounMany meanings which can be expressed by sentences often can be expressed by nouns. Therefore using nouns can make business information gathered, in line with the principle of economic capacity in business communication. In addition, using nouns could avoid involving tenses, voice, and other factors. It also can make entire text appears to be objective, formal and rigorous. Therefore, in business English, we should strive for precision when translating nouns.2.1 As a Countable Noun2.1.1 A Thing That Is Put over or on Another ThingIt means “a thing that is put over or on another thing usually to protect it or to decorate it and should be usually translated into “覆盖物”, “掩蔽物”, “套子”, “罩子” or “盖子”.2.1.2 The Usage in Some Postal TermsIt means “the outside of a book、a magazine or a package” and should be translated into “封皮”, “封袋” or “包封”. A s these meanings, “cover” is often c onstituted idioms, for example: “under cover”, “under separate cover”, “under registered cover”, “in a separate cover” and so on. “ under cover” is usually translated into “附在信中、随函邮寄”;“under separate cover” or “in a separate cover” is usually translated into “另函邮寄” or “另行邮寄”;“under registered cover” is usually translated into “挂号信、挂号函、挂号邮寄”As these meanings, translators must accurately master business terminologies. The biggest characteristic of business English is to use professional vocabulary. Using professional vocabulary can avoid lengthy explanation and improve efficiency.2.1.3 ExcuseIt means “a false reason that you give for doing something in order to hide the real reason” and should be translated into “借口” or “掩饰”.2.2 As an Uncountable Noun2.2.1 A Place That Provides ShelterIt means “from bad weather or protection from an attack” and should be translated into “躲避处”,“避难所” or “庇护所”. This meaning usually appears in everyday English.In order not to miss the point, this article lists a few examples about it, although this meaning is not part of business areas.2.2.2 Protection That an Insurance Company ProvidesIt means “protection that an insurance company provides by promising to pay you money if a particular event happens” and should be translated into “保险”.3 Meanings and Usages as a VerbVerbs in English, like those in other Western languages, have inflexion in number,person, tense, voice and mood, which are considered indispensable to make the sentence clear and easy to understand. But this is not the case with verbs in Chinese. A translator must pay more attention to tense, aspects and passives of verbs in English. This chapter will deal with the E-C translation of the verb “cover”.3.1 As a Transitive Verb3.1.1 To Include or Deal with a Particular Subject or Group of ThingsIt means “to include or deal with a particular subject or group of things” and should be translated into “包含”,“包括” or “涉及”. The past participle of the word “cover”, “covered”, can be regarded as attributive and translated into “……项下的……”.3.1.2 To Buy Something, to Obtain by Paying Money or to Order the GoodsIt means “to buy something” and should be translated into “购进” As this meaning, it us ually uses “requirement” as object. When the meaning is “to order the goods”, it is translated into “定购”and usually uses “order” as object.3.1.3 To Cope withIt means “to cope with” and should be translated into “适应”, “适用于” or “应付”.3.1.4 To Be Sufficient to Defray, Meet, or Offset the Cost or Charge ofIt means “to be sufficient to defray, meet, or offset the cost or charge of” and should be translated into “(足额)支付”“偿付”“补偿”,“弥补” or “补进”.3.1.5 To InsureIt means “to insure” and should be translated into “投保” or “给……保险”.As this meaning, it has many usages in business contracts.3.1.6 To Lie or Spread over the Surface of SomethingIt means “to lie or spread over the surface of something” and should be translated into “覆盖”, “涵盖”, “盖住” or “淹没”. This meaning usually appears in everyday English.In order not to miss the point, this article lists a few examples about it, although this meaning is not part of business areas.3.1.7 To Report on an Event for Television, a Newspaper, etc.It means “to report on an event for television, a newspaper, etc. to show how an event on television” and should be translated into “报道” or “采访”.3.1.8 To Travel the Distance or to Spread over the Area MentionedIt means “to travel the distance mentioned or to spread over the area mentioned” and should be translated into “行走(一段路程)”, “占(一片面积)”. This meaning usually appears in everyday English. In order not to miss the point, this article lists a few examples about it, although this meaning is not part of business areas.3.1.9 To DiscussIt means “to discuss” and should be translated into “讨论”.3.2As an Intransitive Verb3.2.1 To Do S omebody’s Work or Duties While They Are awayIt means “t o do somebody’s work or duties while they are away”and should be translated into “代替”, “顶替” or “替补”.3.2.2 To Invent a Lie or an ExcuseIt means “to invent a lie or an excuse that will stop somebody from getting into trouble” and should be translated into “遮掩”, “掩盖” or “敷衍”.4 The Usage and the E-C Translation of the C over’s DerivativesNot only the word “cover” can be used in many aspects, but also its derivatives are used frequently. Mainly include “coverage” and “covering”.4.1 Coverage as a Noun4.1.1 It Means Insurance Types as an Uncountable NounAs an uncountable noun or a singular noun (without a plural form), it means “insurance types” and should be translated into “保险事务”, “险别”, or “……险”.4.1.2 It Means the Amount of Insurance as an Uncountable NounAs an uncountable noun, “coverage” means “the amount of insurance”and should be translated into “投保额”.4.1.3 It Means Insurance as an Uncountable NounAs an uncountable noun, it means “insurance” and should be translate d into “保险”.4.2 Covering as an Adjective4.2.1 Connected with SomethingIt means “connected with something; belonging to something; be part of something; relating to something” and should be translated into “有关的”, “关于”, “……项下的……” or “……的……”.6 ConclusionYan Fu’“faithfulness, expressiveness and e legance”is recognized as the criteria of translation, and it has far-reaching impact on business English translation. The language of business English is rigorous, accurate. That means “faithful ness”. There are lots of differences between business English translation and ordinary English translation. In ordinary English translation, the translators only have to master two kinds of language and their culture and translation skills, then the translation may be successful. In business English translation, sometimes we know the meanings of every terms but can not translate the whole sentence. Because business English translation is also related to extensive understanding for economy, trade, legal, finance and other aspects. The translation of business English requests the translator have better knowledge of businessterminologies and flexible usages for various types of business discourses.To sum up, the word “cover”and its derivatives have many kinds of meanings and usages in business English. If we want to master them, we should learn their functions in different contexts. On this basis, we also should consider the Chinese speaking logic.The word “cover” and its derivatives are illustrated in this paper for the purpose of further understanding and appropriate usage for the readers.References[1] A S Hornby. Oxford Advanced Learner’s English-Chinese Dictionary[M]. Sixth edition. Oxford: Oxford University Press. 2004: 389-390.[2]梁志坚.商务英语Cover及其派生词的用法及汉译[J].中国科技翻译,2005,18(3):44-49.[3]段梦敏.现在商务英语翻译策略[J].中国科技翻译,2005,18(3):34-36.[4]赵立民.外贸函电用语实用手册[M].北京:对外经济贸易大学出版社.2007:98-248.[5]荣民,尹德永.涉外经贸法律英语[M].北京:首都经济贸易大学出版社,2000:14-28.[6]汪文格,郑卫.实用商务英语[M].湖南:湖南人民出版社,2004:66-145.[7]廖瑛,莫再树.国际商务英语语言与翻译研究[M].第二版.北京:对外经济贸易大学出版社,2007:191-217.[8]吕昊,刘显正,罗萍.商务合同写作及翻译[M].武汉:武汉大学出版社,2005:51-65.[9]车丽娟,贾秀海.商务英语翻译教程[M].北京:对外经济贸易大学出版社,2007:139-199.[10]周保国.商务交际英语[M].武汉:武汉大学出版社,2000:123-240.“cover”一词多义的理解及其在商务英语中的翻译技巧摘要:在经济日益全球化,商务活动日益频繁的今天,商务英语的重要性日益突出。